Split tiles, per se, are formed by extruding a raw clay material in a hollow-walled manner providing two relatively thin outer sidewalls on either side of the longitudinal extrusion axis. The sidewalls are separated by a rib structure and the exterior of the sidewalls may be stamped or pressed with a desired tile geometry (perhaps ornamental). The hollow column is cut into appropriate or predetermined lengths (either before or after stamping) which lengths are then hacked and fired. The final desired ceramic tile product is produced by splitting the fired hollow wall structure and by breaking out any previously stamped tile geometries.
The automatic extrusion cutting and/or stamping of split tile structures as well as the automatic spaced-apart placing of cut lengths of pallets for drying purposes is described in my aforesaid co-pending applications and/or is otherwise known in the art. However, such known methods and apparatus for cutting extruded hollow-walled split tile columns have not provided the ease for efficiencies provided by the present invention and required much greater processing times.
Of the known methods for cutting extruded columns one employs wires or stamping tools arranged to approach an extruded column to complete the cut. When cutting high tile columns with such known prior art wire cutters, the wire has been known to bend to the point where a cut is not fully completed, constituting a serious disadvantage. Likewise, the edges from which the wire cutter exits must be properly supported so that corners or areas along the cut line will not be lifted off as a wire exits the column. It is also known that extruded columns have an extrusion skin which can be torn by the friction created when cutting tools enter the column from the side, resulting in deformation near the edge of the tile along the cut line.
Another known cutting approach involves a multi-step procedure in which the column is initially grooved by a pinching type of motion along what should be the ultimate cutting line. Thereafter, the grooved column is lifted vertically through a wire cutting frame in which the wires are arranged in a pattern matching the previously formed grooves so that the section becomes divided into predetermined portions of tile lengths. Quite obviously, such a device requires elaborate and time-consuming adjustments prior to cutting in order to properly align the grooving and cutting tools and equally elaborate, time-consuming adjustment when changing to cut different patterns (i.e. when tile lengths are changed). In addition, because cutting wires tend to follow a line of least resistance, which because of laminations within the column may not always be in a straight line, it is difficult to precisely position the groove with the cut line.
A still further cutting system for split tiles makes use of special knives arranged to close in a pinching movement toward the extruded column. Lower parts of such knives groove the column while upper parts, arranged to overlap, cut the column as the knife structure is pulled downward through that column. This cutting system has the distinct disadvantage of not being efficient in its cutting approach since the knife structure only cuts on the downward stroke requiring the structure to be opened, at the bottom of the stroke, lifted vertically to the starting height of the stroke and then closed to the initial cutting position prior to the next cutting cycle. Further, such equipment is mechanically elaborate and to achieve cutting efficiencies necessary for a commercial operation capable of producing necessary production speed requires a great number of knives cutting several tiles simultaneously. Further, it is difficult and time-consuming to adjust this type of apparatus for different cut lengths. Clay varies between lean and fat, plastic or sticky types thus presenting different cutting requirements. When cutting clay columns comprised of a plastic or sticky-type of clay, material tends to stick to knives pulled through the column with the increased bulk causing additional deformation of the tile ends, such as, for example, a nose on the tile corner where the knife leaves the tile column.
Yet another approach for cutting extruded columns is to initially roll a groove into the face of the tile column and thereafter cut the tile with wires arranged to follow the grooving rollers. Again, a disadvantage of using wires as the cutter is that wires tend to follow the line of least resistance which may not necessarily be along a straight line. Thus, changes in the resistance caused by laminations resulting during extrusion may cause the wire cutting tool to deviate from a desired straight line. Accordingly, straight cuts are not assured and likewise there is no assurance that the cut will align with the groove along their entire length of the cut.